Compare / versions

Opera developer vs stable

Opera's developer channel next to stable on the fleet. Both are on Chromium 155, so the web platform and the TLS and HTTP/2 fingerprint are identical. What gives the developer build away is the "(Edition developer)" suffix in its user agent.

Opera

On the fleet, Opera runs as stable and developer. Opera stopped shipping Linux betas, so developer is its only pre-release channel; beta is still accepted as a deprecated alias for it. Measured the same night: Opera 140.0.6072.0 developer on Chromium 155.0.8059.2, and Opera 139.0.6053.38 stable on Chromium 155.0.8059.85. That's a new Opera major on the same Chromium major. Unlike Chrome, Opera has no pinned versions, so this page compares the next release with the current one. How Opera differs from Chrome is in Opera vs Chrome; what changed in the last stable major is in the Opera 139 post.

What differs, measured on the fleet

The user agent: developer ends in OPR/140.0.0.0 (Edition developer), stable in OPR/139.0.0.0. Both say Chrome/155.0.0.0.
The client hints: brands Opera 140 vs Opera 139; both send Chromium 155 and the same Not(A:Brand 24 placeholder, in the same order. In the full version list the Chromium build is 155.0.8059.2 on developer and 155.0.8059.85 on stable.
Nothing else. Every web platform feature in our probe reads the same on both builds. That includes the Chromium 155 set (margin-trim, symbols(), text-decoration-skip-spaces, the media-playback-while-not-visible policy) and Topics, Protected Audience, fenced frames and navigator.connection. Neither build has the Chromium 156 or 157 features (CSS random(), scroll-snap-type: pair, text-decoration-inset, streamAppendHTML).

What a site sees

	Opera developer (140)	Opera stable (139)
User agent	`Chrome/155.0.0.0 … OPR/140.0.0.0 (Edition developer)`.	`Chrome/155.0.0.0 … OPR/139.0.0.0`.
Client hints	`Opera 140`, `Chromium 155`, `Not(A:Brand 24`; full versions `140.0.6072.0` / `155.0.8059.2`.	`Opera 139`, `Chromium 155`, `Not(A:Brand 24`; full versions `139.0.6053.38` / `155.0.8059.85`.
TLS and HTTP/2	JA4 `t13d1517h2_8daaf6152771_cb7bf5808d99`, 16 ciphers / 19 extensions, plus the same peetprint, HTTP/2 SETTINGS and header order. JA3 differs between connections because of GREASE.	Identical.
Fingerprint	Canvas hash `f5a94624`, SwiftShader WebGL, 5 plugins, PDF viewer, `en-US, en`, UTC, 1280×720 screen, `webdriver` false.	Identical.
Bot checks	bot.sannysoft.com: 1 of 57 flagged ("WebGL Renderer").	The same.
Plain HTTP	`http://ip-api.com/json` loaded over HTTP (200), no warning page.	The same.
Playwright	Main-world evaluate, console events, init scripts, routing, screenshots, PDF, device emulation and tracing all work.	The same.

For scraping and detection

"(Edition developer)" is a tell. A site that logs user agents sees a pre-release Opera build, which few real visitors run. Use channel: "developer" to see what the next Opera changes, not to blend in.
The developer build gives you nothing new to test today. Its web platform is stable's, so a site behaves the same on both unless it reads the version strings.
Both builds have the same TLS and HTTP/2 fingerprint. JA4 t13d1517 (19 extensions) is the one Chrome sent in Opera vs Chrome. Brave sends t13d1516 (Brave beta vs stable), so Opera's fingerprint is one extension apart from Brave's on either channel.
Plain HTTP works on both, because both are still on Chromium 155. Chromium 157 turns on HTTPS-First mode, which upgrades or blocks http:// URLs (Chrome 157 post). Our nodes switch it off for Chrome, Chromium, Brave and Edge, but that switch-off doesn't cover Opera yet. Re-check plain-HTTP targets when Opera moves to Chromium 157.
The core count (8 vs 64) differed because the two sessions landed on different nodes. It isn't a version difference.

Configurable — by you, by us, by nobody

Item	Who controls it	How
Which build runs	You	`channel: "developer"` for 140 (not `"dev"`; `"beta"` is a deprecated alias), nothing for stable (139). See the opera-developer recipe and the Opera page.
The "(Edition developer)" suffix	Opera	Part of the developer build's own user agent; stable doesn't send it.
Chromium base of each channel	Opera	Both channels are on Chromium 155 today.
CDP access	You	`cdp: true` works on both channels (see the opera-cdp recipe).

Measured on the fleet (2026-11-08)

One headful launch of each channel on the production fleet, through the same proxy, probed from inside a page and via tls.peet.ws. Timings are a single sample, and core counts are the node's.

Launch and cost

Single run; timings depend on the proxy and on fleet load.

	Opera developer	Opera stable
Launch body	{"headless":false,"channel":"developer"}	{"headless":false}
Threads used	2 (linux_headful)	2 (linux_headful)
Browser version	155.0.8059.2	155.0.8059.85
Launch request → browser ready	0.5 s	0.6 s
Playwright connect	0.0 s	0.1 s
Load example.com	0.7 s	1.2 s
Load tls.peet.ws/api/all	1.5 s	1.2 s

What the network sees

From tls.peet.ws/api/all, requested by the browser itself. JA3 hashes change between runs of the same build (GREASE), so compare JA4 and the HTTP/2 fingerprint.

	Opera developer	Opera stable
HTTP version	h2	h2
JA4	t13d1517h2_8daaf6152771_cb7bf5808d99	t13d1517h2_8daaf6152771_cb7bf5808d99
Peetprint hash	fc97c1cdfb1409c9a9326c1b726d1dee	fc97c1cdfb1409c9a9326c1b726d1dee
Akamai HTTP/2 fingerprint	1:65536;2:0;4:6291456;6:262144\|15663105\|0\|m,a,s,p	1:65536;2:0;4:6291456;6:262144\|15663105\|0\|m,a,s,p
Cipher suites / extensions	16 / 19	16 / 19
Header order (first 12)	method, authority, scheme, path, sec-ch-ua, sec-ch-ua-mobile, sec-ch-ua-platform, upgrade-insecure-requests, user-agent, accept, sec-fetch-site, sec-fetch-mode	method, authority, scheme, path, sec-ch-ua, sec-ch-ua-mobile, sec-ch-ua-platform, upgrade-insecure-requests, user-agent, accept, sec-fetch-site, sec-fetch-mode

What page scripts see

Read with page.evaluate on example.com. Cores and memory are the server's and vary between fleet nodes.

	Opera developer	Opera stable
navigator.userAgent	Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/155.0.0.0 Safari/537.36 OPR/140.0.0.0 (Edition developer)	Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/155.0.0.0 Safari/537.36 OPR/139.0.0.0
UA-CH brands	Opera 140 · Chromium 155 · Not(A:Brand 24	Opera 139 · Chromium 155 · Not(A:Brand 24
UA-CH full version list	Opera 140.0.6072.0 · Chromium 155.0.8059.2 · Not(A:Brand 24.0.0.0	Opera 139.0.6053.38 · Chromium 155.0.8059.85 · Not(A:Brand 24.0.0.0
navigator.platform / vendor	Linux x86_64 / Google Inc.	Linux x86_64 / Google Inc.
Languages	en-US, en	en-US, en
Timezone / locale	UTC / en-US	UTC / en-US
Screen (w×h×availW×availH×depth)	1280x720x1280x720x24	1280x720x1280x720x24
Window outer / inner / DPR	1288x805 / 1280x720 / 1	1288x805 / 1280x720 / 1
hardwareConcurrency / deviceMemory	8 / 32	64 / 32
WebGL vendor	Google Inc. (Google)	Google Inc. (Google)
WebGL renderer	ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)	ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)
WebGL version	WebGL 2.0 (OpenGL ES 3.0 Chromium)	WebGL 2.0 (OpenGL ES 3.0 Chromium)
WebGPU (navigator.gpu)	yes	yes
Canvas hash	f5a94624	f5a94624
navigator.webdriver	no	no
window.chrome / navigator.connection	yes / yes	yes / yes
Plugins / PDF viewer	5 / yes	5 / yes
Notification.permission / permissions.query	default / prompt	default / prompt

Web platform features

Presence probes; a user agent that claims one version while exposing another's features is a detectable inconsistency.

	Opera developer	Opera stable
`Iterator.prototype.includes` (new in Chrome 154)	yes	yes
`FontFace.width` (new in Chrome 154)	yes	yes
CSS `text-decoration-inset` (Chrome 157)	no	no
`Iterator.prototype.join` (Chrome 153)	yes	yes
`Iterator.zip` (Chrome 153)	yes	yes
CSS `scroll-axis-lock` (Chrome 153)	no	no
`<camera>` element (Chrome 153)	yes	yes
`document.requestStorageAccessFor` (deprecated in 153)	no	no
Topics API (`document.browsingTopics`)	yes	yes
Protected Audience (`navigator.joinAdInterestGroup`)	yes	yes
Shared Storage (`window.sharedStorage`)	no	no
Attribution Reporting (`window.attributionReporting`)	no	no
Private Aggregation	no	no
WebHID (`navigator.hid`)	yes	yes
CSS `margin-trim` (Chrome 155)	yes	yes
CSS `text-decoration-skip-spaces` (Chrome 155)	yes	yes
CSS `corner` shorthand (listed for Chrome 160)	no	no
CSS `symbols()` (Chrome 155)	yes	yes
`Element.streamAppendHTML` (Chrome 157)	no	no
`WebTransport.reliability` (on stable from Chrome 157; listed for 158)	no	no
`window.maximize()` — Additional Windowing Controls (Chrome 155)	no	no
Canvas `srgb-linear` colour space (on stable from Chrome 157)	no	no
Permission policy `media-playback-while-not-visible` (Chrome 155)	yes	yes
CSS `random()` (Chrome 156)	no	no
CSS `scroll-snap-type: pair` (Chrome 156)	no	no
Fenced frames (`window.fence`)	yes	yes
`rel=compression-dictionary` (Chrome 156 updates)	yes	yes

bot.sannysoft.com

The classic headless-detection test page; what it marks red.

	Opera developer	Opera stable
Checks / failed	57 / 1	57 / 1
Failed checks	WebGL Renderer	WebGL Renderer

A plain-HTTP URL (http://ip-api.com/json)

Chrome 154 warns before loading insecure HTTP by default — does that reach an automated session?

	Opera developer	Opera stable
Final URL	http://ip-api.com/json/?fields=status	http://ip-api.com/json/?fields=status
HTTP status	200	200
Content loaded / warning page first	yes / no	yes / no

Playwright over the remote connection

Which client features work on this side.

	Opera developer	Opera stable
page.evaluate runs in the page's own world	yes	yes
addInitScript visible to page scripts	yes	yes
Console events	yes	yes
Request interception (page.route)	yes	yes
Screenshot	yes	yes
PDF	yes	yes
Mobile device emulation	yes	yes
Tracing	yes	yes

Rows where the two sides differ are highlighted. IP addresses are replaced with placeholders (203.0.113.x). The probe is compare/probe.mjs in our repository; the raw result is below.

Raw output

{
  "ran_at": "2026-11-08T02:06:47.731Z",
  "sides": [
    {
      "label": "Opera developer",
      "engine": "opera",
      "body": {
        "headless": false,
        "channel": "developer"
      },
      "launch": {
        "browser": "opera",
        "resource_class": "linux_headful",
        "weight": 2,
        "launch_ms": 545,
        "connect_ms": 37,
        "example_ms": 724,
        "peet_ms": 1472
      },
      "network": {
        "http_version": "h2",
        "ja4": "t13d1517h2_8daaf6152771_cb7bf5808d99",
        "ja3_hash": "83375184e0a7d5b481bb56b9b04f90bc",
        "peetprint_hash": "fc97c1cdfb1409c9a9326c1b726d1dee",
        "ciphers": 16,
        "extensions": 19,
        "akamai_h2": "1:65536;2:0;4:6291456;6:262144|15663105|0|m,a,s,p",
        "akamai_h2_hash": "52d84b11737d980aef856699f885ca86",
        "header_order": [
          "method",
          "authority",
          "scheme",
          "path",
          "sec-ch-ua",
          "sec-ch-ua-mobile",
          "sec-ch-ua-platform",
          "upgrade-insecure-requests",
          "user-agent",
          "accept",
          "sec-fetch-site",
          "sec-fetch-mode"
        ]
      },
      "page": {
        "user_agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/155.0.0.0 Safari/537.36 OPR/140.0.0.0 (Edition developer)",
        "platform": "Linux x86_64",
        "vendor": "Google Inc.",
        "languages": [
          "en-US",
          "en"
        ],
        "hardware_concurrency": 8,
        "device_memory": 32,
        "max_touch_points": 0,
        "webdriver": false,
        "plugins": 5,
        "pdf_viewer": true,
        "ua_data": {
          "brands": [
            {
              "brand": "Opera",
              "version": "140"
            },
            {
              "brand": "Chromium",
              "version": "155"
            },
            {
              "brand": "Not(A:Brand",
              "version": "24"
            }
          ],
          "mobile": false,
          "platform": "Linux",
          "architecture": "x86",
          "bitness": "64",
          "formFactors": [
            "Desktop"
          ],
          "fullVersionList": [
            {
              "brand": "Opera",
              "version": "140.0.6072.0"
            },
            {
              "brand": "Chromium",
              "version": "155.0.8059.2"
            },
            {
              "brand": "Not(A:Brand",
              "version": "24.0.0.0"
            }
          ],
          "model": "",
          "platformVersion": "",
          "uaFullVersion": "140.0.6072.0",
          "wow64": false
        },
        "screen": "1280x720x1280x720x24",
        "window": {
          "outer": "1288x805",
          "inner": "1280x720",
          "dpr": 1
        },
        "timezone": "UTC",
        "locale": "en-US",
        "webgl": {
          "vendor": "Google Inc. (Google)",
          "renderer": "ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)",
          "version": "WebGL 2.0 (OpenGL ES 3.0 Chromium)"
        },
        "canvas_hash": "f5a94624",
        "webgpu": true,
        "chrome_object": true,
        "chrome_runtime": false,
        "notification_permission": "default",
        "notification_query": "prompt",
        "has_focus": true,
        "connection_api": true,
        "stack_read_by_debugger": false,
        "features": {
          "iterator_includes": true,
          "iterator_join": true,
          "iterator_zip": true,
          "fontface_width": true,
          "css_text_decoration_inset": false,
          "css_scroll_axis_lock": false,
          "websocket_options_bag": null,
          "camera_element": true,
          "topics_api": true,
          "protected_audience": true,
          "shared_storage": false,
          "attribution_reporting": false,
          "request_storage_access_for": false,
          "webhid": true,
          "private_aggregation": false,
          "css_margin_trim": true,
          "css_text_decoration_skip_spaces": true,
          "css_corner_shorthand": false,
          "css_symbols": true,
          "stream_append_html": false,
          "webtransport_reliability": false,
          "window_maximize": false,
          "canvas_srgb_linear": false,
          "policy_media_playback_while_not_visible": true,
          "css_random": false,
          "css_scroll_snap_pair": false,
          "fenced_frames": true,
          "compression_dictionary": true
        }
      },
      "page_main_world": null,
      "sannysoft": {
        "checks": 57,
        "failed": 1,
        "failed_names": [
          "WebGL Renderer"
        ],
        "passed": 30
      },
      "plain_http": {
        "final_url": "http://ip-api.com/json/?fields=status",
        "status": 200,
        "title": "",
        "loaded": true,
        "warning_page": false,
        "page_text": "{\"status\":\"success\"}"
      },
      "playwright": {
        "evaluate_in_main_world": true,
        "console_events": true,
        "init_script": true,
        "route": true,
        "screenshot": true,
        "pdf": true,
        "mobile_emulation": true,
        "tracing": true
      },
      "browser_version": "155.0.8059.2"
    },
    {
      "label": "Opera stable",
      "engine": "opera",
      "body": {
        "headless": false
      },
      "launch": {
        "browser": "opera",
        "resource_class": "linux_headful",
        "weight": 2,
        "launch_ms": 591,
        "connect_ms": 125,
        "example_ms": 1173,
        "peet_ms": 1234
      },
      "network": {
        "http_version": "h2",
        "ja4": "t13d1517h2_8daaf6152771_cb7bf5808d99",
        "ja3_hash": "22fb104ac7d5ee7397570b059e22c421",
        "peetprint_hash": "fc97c1cdfb1409c9a9326c1b726d1dee",
        "ciphers": 16,
        "extensions": 19,
        "akamai_h2": "1:65536;2:0;4:6291456;6:262144|15663105|0|m,a,s,p",
        "akamai_h2_hash": "52d84b11737d980aef856699f885ca86",
        "header_order": [
          "method",
          "authority",
          "scheme",
          "path",
          "sec-ch-ua",
          "sec-ch-ua-mobile",
          "sec-ch-ua-platform",
          "upgrade-insecure-requests",
          "user-agent",
          "accept",
          "sec-fetch-site",
          "sec-fetch-mode"
        ]
      },
      "page": {
        "user_agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/155.0.0.0 Safari/537.36 OPR/139.0.0.0",
        "platform": "Linux x86_64",
        "vendor": "Google Inc.",
        "languages": [
          "en-US",
          "en"
        ],
        "hardware_concurrency": 64,
        "device_memory": 32,
        "max_touch_points": 0,
        "webdriver": false,
        "plugins": 5,
        "pdf_viewer": true,
        "ua_data": {
          "brands": [
            {
              "brand": "Opera",
              "version": "139"
            },
            {
              "brand": "Chromium",
              "version": "155"
            },
            {
              "brand": "Not(A:Brand",
              "version": "24"
            }
          ],
          "mobile": false,
          "platform": "Linux",
          "architecture": "x86",
          "bitness": "64",
          "formFactors": [
            "Desktop"
          ],
          "fullVersionList": [
            {
              "brand": "Opera",
              "version": "139.0.6053.38"
            },
            {
              "brand": "Chromium",
              "version": "155.0.8059.85"
            },
            {
              "brand": "Not(A:Brand",
              "version": "24.0.0.0"
            }
          ],
          "model": "",
          "platformVersion": "",
          "uaFullVersion": "139.0.6053.38",
          "wow64": false
        },
        "screen": "1280x720x1280x720x24",
        "window": {
          "outer": "1288x805",
          "inner": "1280x720",
          "dpr": 1
        },
        "timezone": "UTC",
        "locale": "en-US",
        "webgl": {
          "vendor": "Google Inc. (Google)",
          "renderer": "ANGLE (Google, Vulkan 1.3.0 (SwiftShader Device (Subzero) (0x0000C0DE)), SwiftShader driver)",
          "version": "WebGL 2.0 (OpenGL ES 3.0 Chromium)"
        },
        "canvas_hash": "f5a94624",
        "webgpu": true,
        "chrome_object": true,
        "chrome_runtime": false,
        "notification_permission": "default",
        "notification_query": "prompt",
        "has_focus": true,
        "connection_api": true,
        "stack_read_by_debugger": false,
        "features": {
          "iterator_includes": true,
          "iterator_join": true,
          "iterator_zip": true,
          "fontface_width": true,
          "css_text_decoration_inset": false,
          "css_scroll_axis_lock": false,
          "websocket_options_bag": null,
          "camera_element": true,
          "topics_api": true,
          "protected_audience": true,
          "shared_storage": false,
          "attribution_reporting": false,
          "request_storage_access_for": false,
          "webhid": true,
          "private_aggregation": false,
          "css_margin_trim": true,
          "css_text_decoration_skip_spaces": true,
          "css_corner_shorthand": false,
          "css_symbols": true,
          "stream_append_html": false,
          "webtransport_reliability": false,
          "window_maximize": false,
          "canvas_srgb_linear": false,
          "policy_media_playback_while_not_visible": true,
          "css_random": false,
          "css_scroll_snap_pair": false,
          "fenced_frames": true,
          "compression_dictionary": true
        }
      },
      "page_main_world": null,
      "sannysoft": {
        "checks": 57,
        "failed": 1,
        "failed_names": [
          "WebGL Renderer"
        ],
        "passed": 30
      },
      "plain_http": {
        "final_url": "http://ip-api.com/json/?fields=status",
        "status": 200,
        "title": "",
        "loaded": true,
        "warning_page": false,
        "page_text": "{\"status\":\"success\"}"
      },
      "playwright": {
        "evaluate_in_main_world": true,
        "console_events": true,
        "init_script": true,
        "route": true,
        "screenshot": true,
        "pdf": true,
        "mobile_emulation": true,
        "tracing": true
      },
      "browser_version": "155.0.8059.85"
    }
  ]
}

Bottom line

Opera 140 developer is the same browser as 139 stable as far as a page or the network can tell. It runs on the same Chromium 155 and has the same fingerprint, and only the version strings and the "(Edition developer)" suffix differ. Code that runs on stable needs no change.

The developer channel matters once Opera moves to Chromium 157: that is where a new Chromium base should show up first, together with its features and HTTPS-First mode.